Re: [RFC][PATCH 12/12] PM / r8169: Add simplified run-time PM support

Rafael J. Wysocki
2010-01-03T21:01:14Z

On Sunday 03 January 2010, Pavel Machek wrote:
>
> > > On notebooks, you can often use
> > >
> > > pavel@amd:/data/l/linux-msm/arch/arm/mach-msm$ cat
> > > /proc/acpi/battery/BAT0/state
> > > present: yes
> > > capacity state: ok
> > > charging state: charged
> > > present rate: 0 mW
> > > remaining capacity: 71830 mWh
> > > present voltage: 16277 mV
> > >
> > > ...present rate is often usable-enough.
> >
> > Using /proc/acpi/battery/BAT1/state I measured the energy drawn in 10 minutes
> > both with the network adapter in D0 and D3hot. The results were that with the
> > network adapter in D0 the box drew 2476 mWh, while with the network adapter in
> > D3hot it drew 2361 mWh. The difference is 115 mWh, or about 5% on this
> > particular box.
> >
> > This means about 0.1 Wh in 10 minutes, so we can save about 0.6 Wh per hour.
>
> Which means it saves 0.6W :-). Measuring power in Wh/h is "interesting".

You can't save power, you can only save energy. Wh is just an energy unit.

> Ok, that's consistent with my experiments, ethernet transciever was around 1W... Thanks.

No big deal.

Rafael